Internal friction and mode relaxation in a simple chain model.
نویسندگان
چکیده
We consider the equilibrium relaxation properties of the end-to-end distance and of the principal components in a one-dimensional polymer chain model with nonlinear interaction between the beads. While for the single-well potentials these properties are similar to the ones of a Rouse chain, for the double-well interaction potentials, modeling internal friction, they differ vastly from the ones of the harmonic chain at intermediate times and intermediate temperatures. This minimal description within a one-dimensional model mimics the relaxation properties found in much more complex polymer systems. Thus, the relaxation time of the end-to-end distance may grow by orders of magnitude at intermediate temperatures. The principal components (whose directions are shown to coincide with the normal modes of the harmonic chain, whatever interaction potential is assumed) not only display larger relaxation times but also subdiffusive scaling.
منابع مشابه
Microtubule dynamics depart from the wormlike chain model.
Thermal shape fluctuations of grafted microtubules were studied using high resolution particle tracking of attached fluorescent beads. First mode relaxation times were extracted from the mean square displacement in the transverse coordinate. For microtubules shorter than approximately 10 microm, the relaxation times were found to follow an L2 dependence instead of L4 as expected from the standa...
متن کاملDynamic mechanical response of polymer networks
The dynamic-mechanical response of flexible polymer networks is studied in the framework of tube model, in the limit of small affine deformations, using the approach based on Rayleighian dissipation function. The dynamic complex modulus G∗(ω) is calculated from the analysis of a network strand relaxation to the new equilibrium conformation around the distorted primitive path. Chain equilibratio...
متن کاملZener Relaxation in Al-Li Binary Alloys
Internal friction (I.F.) and modulus measurements have been carried out as a function of temperature in order to study the Li mobility in an A1 8.1 at% Li 0.03 at% Zr alloy. The results show that the sequence of 6' and 6 precipitation can be followed through the evolution of the internal friction spectra. Two peaks appear in the internal friction spectrum. The low temperature peak Pz (450 K), h...
متن کاملInternal Friction Peak in Cold-Worked ”Pure” Aluminum and Aluminum Alloys
Low frequency internal friction measurements have been made on "pure" aluminum and dilute aluminum alloys in heavily cold-worked states. A relaxation peak is observed at about 200 K(for 1Hz) even in specimens of nominally 4N or higher purity. This peak is considered to be the same as those previously reported by several researchers for dilute aluminum alloys of Cu, Mg or Ga. Among various eleme...
متن کاملRouse Mode Analysis of Chain Relaxation in Homopolymer Melts
We use molecular dynamics simulations of the Kremer-Grest (KG) bead-spring model of polymer chains of length between 10 and 500, and a closely related analogue that allows for chain crossing, to clearly delineate the effects of entanglements on the length-scale-dependent chain relaxation in polymer melts. We analyze the resulting trajectories using the Rouse modes of the chains and find that en...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of chemical physics
دوره 131 23 شماره
صفحات -
تاریخ انتشار 2009